1. Field of the Invention
The present invention relates to umbrellas and more particularly to a vented umbrella that is resistant to inversion from the wind as well as is effective in ventilating air between the underside of umbrella and the upper side thereof.
2. Description of Related Art
Conventionally, an umbrella is a foldable means carried by people for protection against the rain and/or sun. Further, canopy is typically an opaque cloth with a close texture. This also means the permeability thereof is poor. As such, an umbrella user often feels muggy under the hot sun due to the poor ventilation. To the worse, in a rainy windy day, a wind will catch an umbrella user unaware and exert a force against the inner surface of the canopy which will cause the canopy to invert from its normal operable position to an upwardly convex position.
A conventional windproof umbrella is shown in FIG. 4 wherein umbrella 3 comprises a lower canopy 30 and an upper canopy 31. Lower canopy 30 is in a covering position over the fully stretched ribs 41. A plurality of openings 301 are formed on lower canopy 30 wherein each opening 301 is located between two adjacent ribs 41. Upper canopy 31 is smaller than lower canopy 30 in size. Upper canopy 31 is in a concentric covering relation with respect to lower canopy 30 wherein openings 301 are also covered by upper canopy 31. With this, during windy weather, wind caught beneath the upper canopy 31 exits through the openings 301 and applies pressure to the underside of the lower canopy 30. This forces lower canopy 30 lift away from upper canopy 31 to provide a path for wind to escape the umbrella 3.
Another conventional windproof umbrella is shown in FIG. 5 wherein umbrella 5 comprises a lower canopy 50 and an upper canopy 51. Lower canopy 50 is in a covering position over the fully stretched ribs 61. A multilateral canopy 501 is in a concentric covering relation with respect to lower canopy 50. This umbrella 5 also can ventilate air through canopy 501.
But these are unsatisfactory for the purpose for which the invention is concerned for the following reasons:
1. Ventilation is poor. In detail, upper canopy is in a close covering relation with respect to lower canopy, whereby only a small vent exists between upper canopy and lower canopy for ventilating when a strong wind applies pressure to the underside of lower canopy. PA1 2. Cost ineffective. It is seen that lower canopy and upper canopy are relatively large. Further, the covering area of upper canopy with respect to lower canopy is also large, resulting in an increase in the manufacturing cost. PA1 3. Complex manufacturing processes. The provision of openings inevitably complicates the manufacturing processes.
A still another conventional windproof umbrella is shown in FIGS. 6 and 7. This one eliminates the drawbacks of above two prior art umbrellas. In detail, peripheral edge 211 of upper canopy 21 is held taut by attaching elastic strips 22 to the fasteners 121 on stretchers 12 to form a plurality of V-shapes. This can prevent elastic strips 22 from sliding along the stretchers 12 as shown in FIG. 7. A plurality of large openings 204 are formed in the umbrella. However, elastic strips 22 generally have the same orientation as ribs 11, i.e., nearly parallel each other. Also, peripheral edge 211 of upper canopy 21 is partially closed by the open openings 204. To the worse, openings 204 may be closed by a strong wind coming from above the top of umbrella as indicated by arrow A. Thus the ventilation is poor. Further, the elasticity of elastic strips 22 will be worn out as time passes because the elastic strips 22 are often stretched. This in turn causes openings 204 to shrink. Furthermore, the provision of fasteners 121 is time consuming in assembly, resulting in an increase in the manufacturing cost.